Liquid Nitrogen Plumbing

LN2 Plumbing

Liquid nitrogen,
commonly referred to simply as LN2, is a
compact and easily transported source of very dry nitrogen.
Handled carefully, it is a much safer source of
extremely cold and dry air than pressurized gas.
Large containers called Dewar flasks can keep it
cold and liquid for days to weeks at a time.
Sometimes you see these dewars filled with liquid nitrogen
sitting on sidewalks in major cities.
They are used to keep telecommunications conduits dry.

Liquid nitrogen is a clear liquid that looks much like
water and is slightly less dense —
0.807 g/mL or just 80.7% the density of water.
It is, however, extremely cold.
It boils at 77 K
(–195° C or –321° F).

A
Dewar,
named for the Scottish physicist and chemist
James Dewar,
who invented it in 1892,
is a large vacuum flask used to store liquid nitrogen for
periods of days to a few weeks.
A big one for scientific and industrial applications is
often called a Dewar,
while a small one for your coffee is often called
a Thermos,
generally speaking they're all vacuum flasks.

A vacuum between the inner and outer walls minimizes
heat transfer.
A small fraction of the liquid nitrogen boils off,
holding the body of the liquid at 77 K.
Nitrogen expands by a factor of 1:694 going from the
liquid to the gaseous phase, so the dewer must be unstoppered
or, more likely, stoppered with a pressure relief value.

New York's Financial District is at the very southern tip
of the island of Manhattan, in the narrow twisting streets
of old Nieuw-Amsterdam.
There are huge numbers of telecommunications lines
running through a small area just a few meters above the
water line, where the East River and the Hudson River
join in New York Harbor.

So, in New York it is pretty common to see Dewars
of liquid nitrogen sitting along the street.
They're often chained to a streetlight pole.
A small red rubber hose is duct-taped to the ground and
disappears into a manhole cover.

Here you see two
Dewar vacuum flasks of liquid nitrogen along Nassau Street,
leading toward the New York Stock Exchange, at which point
its name changes to Broad Street.
The NYSE is on the corner of Broad and Wall Streets,
fronting on Broad.
That's its columned front with the large American flag
in the background.

There is a guard post just across the street, so these
Dewars have 24/7 protection and aren't chained to anything.

These Dewar vacuum flasks of liquid nitrogen are
on the sidewalk along Broadway where it crosses John Street.

You can see the frost built up on the top plumbing in the
close up view.

60 Hudson Street
is the former Western Union Building and was
its headquarters until 1973.
It is still a major world communications nexus.

It's a carrier hotel with over 100 telecommunications
companies interchanging Internet traffic.
Another major carrier hotel in Lower Manhattan
is at 60 Broad Street, just off Wall Street.

Also, Tuckerton NJ and the surrounding area include the
landing sites for a number of cables to Europe,
the Caribbean, and South America.

My cromwell-intl.com domain appeared in September, 2001,
although the Wayback Machine didn't notice its one enormous
Toilet of the World page until
January 17, 2002.
Some time soon after that I split it into categories,
and the collection has grown ever since.

In December, 2010 I registered the
toilet-guru.com
domain and moved the pages to a dedicated server.